Testing device and its calibration method

Abstract

According to one embodiment, a testing device includes a signal generator that generates a first signal output to a device under test, a channel selector provided after the signal generator and configured to select one of a plurality of channels, a signal receiver that receives the second signal supplied from the device under test, a correction value calculator that calculates a correction value for calibrating loss of a respective one of the channels, wherein the correction value calculator calculates a correction value for calibrating loss of a respective one of the channels included in the channel selector, based on a signal level received by the signal receiver via a loopback channel, when a calibration-level output state indicating a state where a signal level of the first signal generated by the signal generator reaches a predetermined transmission reference level of calibration is assumed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2014-189022, filed Sep. 17, 2014, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a testing device for testing, for example, electrical characteristics of a portable device, and a calibration method employed therein.[0004]2. Description of the Related Art[0005]Conventionally, as this type of a testing device, a mobile-device testing system disclosed in, for example, patent document 1 (JP 2003-18104A), is known. The testing device described in patent document 1 comprises a signal generator for generating signals, an interface unit for switching the channel between the signal generator and a device as a measurement target, and a calibration power meter and a calibration receiver connected to the output side of the interf...

AI Technical Summary

Benefits of technology

The present invention aims to provide a testing device with a short calibration time and a calibration method to achieve this. The testing device selects a channel to calibrate and calculates a correction value for calibrating loss of that channel based on a signal level received by the device via a loopback channel. This can be done in the calibration-level output state. By doing so, the testing device can quickly calibrate without significantly delaying the testing process. This applies to both simplex and duplex communication.

Problems solved by technology

Accordingly, if any of these configurations is adopted in the interface unit, significant signal level loss will occur, resulting in that the testing device does not satisfy test performance required by a device under test.

However, the interface unit must have an amplifier excellent in linearity performance, which will raise problems, such as increases in required power and mounting area, and heat dissipation, resulting in an increase in device cost.

In addition, since no consideration is given to a signal input to the testing device, there is a problem that the signal-to-noise ratio of the input signal will be degraded by a value corresponding to the level loss in the interface unit.

However, in general, there is a problem that the level accuracy of an output and an input will be degraded by fluctuation in gain due to fluctuation with time in the performance of the amplifier or due to fluctuation in temperature.

In this case, however, the interface unit must comprise the level detector, which inevitably increases the device mounting area to thereby increase the device cost.

This problem becomes serious in proportion to the number of signal generators.

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